BirdAnalyst
Species · BCR 32 · BBS 2025 Release · 1966–2024

Olive-sided Flycatcher In Coastal California

All regionsCoastal CaliforniaAerial insectivores

Olive-sided Flycatcher in Coastal California has fallen sharply: down 56% on the route-weighted index since 1970.

-56%Since 1970TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
64Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Olive-sided Flycatcher has fallen sharply in Coastal California: down 56% on the route-weighted index since 1970.

Olive-sided Flycatcher In Coastal California Population Forecast

If the recent trend holds, Olive-sided Flycatcher in Coastal California is projected to fall about 43% by 2029 — from 1.3 in 2024 to a central estimate of 0.76 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±30.6%, with 100% of held-out values landing inside the 95% band.

-43%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.76Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.995% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±30.6%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Olive-sided Flycatcher in Coastal California is projected to fall about 43% by 2029 — from 1.3 in 2024 to a central estimate of 0.76 (95% range 0.00–1.9). A 5-year backtest shows a typical error of ±30.6%, with 100% of held-out values landing inside the 95% band.19682029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.860.002.0
20260.830.002.0
20270.810.001.9
20280.790.001.9
20290.760.001.9

Routes In Coastal California

Routes recording Olive-sided Flycatcher in Coastal California.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Waterman GapCALIFORNIA262024
PescaderoCALIFORNIA132024
Mt PinosCALIFORNIA122004
ValyermoCALIFORNIA122019
San Benito Mtn.CALIFORNIA112009
Point ReyesCALIFORNIA102023
Mt Pinos 2CALIFORNIA82024
FairfaxCALIFORNIA72024
Elizabeth LkCALIFORNIA71991
Green ValleyCALIFORNIA52023
Lake CachumaCALIFORNIA52016
ParkfieldCALIFORNIA41977
PowayCALIFORNIA41979
FallsvaleCALIFORNIA41981
Mt LagunaCALIFORNIA41981
Glen EllenCALIFORNIA42004
Sawmill MtnCALIFORNIA31996
LockwoodCALIFORNIA32024
ColmaCALIFORNIA21972
Foster ParkCALIFORNIA21992
Lake SuccessCALIFORNIA21996
Morro BayCALIFORNIA21991
Big BearCALIFORNIA21986
El ToroCALIFORNIA21983
JacumbaCALIFORNIA21992

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.